From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
"Theodore Ts'o" <tytso@mit.edu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Dave Chinner <david@fromorbit.com>,
Ingo Molnar <mingo@redhat.com>, Jan Kara <jack@suse.com>,
Jeff Layton <jlayton@poochiereds.net>,
Matthew Wilcox <willy@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nvdimm@ml01.01.org, x86@kernel.org,
xfs@oss.sgi.com, Andrew Morton <akpm@linux-foundation.org>,
Dan Williams <dan.j.williams@intel.com>,
Matthew Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: [PATCH v3 3/7] mm: add find_get_entries_tag()
Date: Tue, 8 Dec 2015 12:18:41 -0700 [thread overview]
Message-ID: <1449602325-20572-4-git-send-email-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <1449602325-20572-1-git-send-email-ross.zwisler@linux.intel.com>
Add find_get_entries_tag() to the family of functions that include
find_get_entries(), find_get_pages() and find_get_pages_tag(). This is
needed for DAX dirty page handling because we need a list of both page
offsets and radix tree entries ('indices' and 'entries' in this function)
that are marked with the PAGECACHE_TAG_TOWRITE tag.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
include/linux/pagemap.h | 3 +++
mm/filemap.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 26eabf5..4db0425 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -361,6 +361,9 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages);
+unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
+ int tag, unsigned int nr_entries,
+ struct page **entries, pgoff_t *indices);
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index, unsigned flags);
diff --git a/mm/filemap.c b/mm/filemap.c
index 167a4d9..99dfbc9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1498,6 +1498,74 @@ repeat:
}
EXPORT_SYMBOL(find_get_pages_tag);
+/**
+ * find_get_entries_tag - find and return entries that match @tag
+ * @mapping: the address_space to search
+ * @start: the starting page cache index
+ * @tag: the tag index
+ * @nr_entries: the maximum number of entries
+ * @entries: where the resulting entries are placed
+ * @indices: the cache indices corresponding to the entries in @entries
+ *
+ * Like find_get_entries, except we only return entries which are tagged with
+ * @tag.
+ */
+unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
+ int tag, unsigned int nr_entries,
+ struct page **entries, pgoff_t *indices)
+{
+ void **slot;
+ unsigned int ret = 0;
+ struct radix_tree_iter iter;
+
+ if (!nr_entries)
+ return 0;
+
+ rcu_read_lock();
+restart:
+ radix_tree_for_each_tagged(slot, &mapping->page_tree,
+ &iter, start, tag) {
+ struct page *page;
+repeat:
+ page = radix_tree_deref_slot(slot);
+ if (unlikely(!page))
+ continue;
+ if (radix_tree_exception(page)) {
+ if (radix_tree_deref_retry(page)) {
+ /*
+ * Transient condition which can only trigger
+ * when entry at index 0 moves out of or back
+ * to root: none yet gotten, safe to restart.
+ */
+ goto restart;
+ }
+
+ /*
+ * A shadow entry of a recently evicted page, a swap
+ * entry from shmem/tmpfs or a DAX entry. Return it
+ * without attempting to raise page count.
+ */
+ goto export;
+ }
+ if (!page_cache_get_speculative(page))
+ goto repeat;
+
+ /* Has the page moved? */
+ if (unlikely(page != *slot)) {
+ page_cache_release(page);
+ goto repeat;
+ }
+export:
+ indices[ret] = iter.index;
+ entries[ret] = page;
+ if (++ret == nr_entries)
+ break;
+ }
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL(find_get_entries_tag);
+
/*
* CD/DVDs are error prone. When a medium error occurs, the driver may fail
* a _large_ part of the i/o request. Imagine the worst scenario:
--
2.5.0
next prev parent reply other threads:[~2015-12-08 19:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-08 19:18 [PATCH v3 0/7] DAX fsync/msync support Ross Zwisler
2015-12-08 19:18 ` [PATCH v3 1/7] pmem: add wb_cache_pmem() to the PMEM API Ross Zwisler
2015-12-08 19:18 ` [PATCH v3 2/7] dax: support dirty DAX entries in radix tree Ross Zwisler
2015-12-18 9:01 ` Jan Kara
2015-12-19 5:23 ` Ross Zwisler
2015-12-08 19:18 ` Ross Zwisler [this message]
2015-12-09 19:44 ` [PATCH v3 3/7] mm: add find_get_entries_tag() Dan Williams
2015-12-10 20:24 ` Ross Zwisler
2015-12-10 20:31 ` Dan Williams
2015-12-18 9:33 ` Jan Kara
2015-12-08 19:18 ` [PATCH v3 4/7] dax: add support for fsync/sync Ross Zwisler
2015-12-08 19:18 ` [PATCH v3 5/7] ext2: call dax_pfn_mkwrite() for DAX fsync/msync Ross Zwisler
2015-12-08 19:18 ` [PATCH v3 6/7] ext4: " Ross Zwisler
2015-12-08 19:18 ` [PATCH v3 7/7] xfs: " Ross Zwisler
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